Drive for loom dobbies



Aug. 17, 1937.

E. R. HOLMES DRIVE FOR LOOM DOBBIES Filed April 11, less 3 Sheets-sheaf 1 Illlll IIIIIIIIIIIIINIII Inventor Hbr'udqe R-Hoh'nes a! T' Attor ey Aug.'17, 1937. E. R. HOLMES DRIVE FOR LOOM DOBBIES Filed April 11, 1936 3 Sheets-Sheet 3 35 Inventor dqe R. Ho\mee Attorney Patented Aug. 17, 1937 UNITE .S'EA'EELS DRIVE F613, LOOlll DOBBIES Application April 11, 1936, Serial No. 73,870

15 Claims.

This invention relates to improvements in driving mechanism for loom dobbies and it is the gen eral object of the invention to provide a mechanism so constructed as to give a variety of types of motion to the knives which engage the dobby hooks.

Loom dobbies ordinarily include in their construction a pair of oppositely reciprocating knives which cooperate with upper and lower sets of 1c hooks. The hooks are connected in pairs to dobby back levers which in turn are pivoted to the jacks which lift the harness frames. It is desirable to vary the rate at which the knives travel so that the shed may remain open a com 15 paratively long time when the lay is in rear position during the travel of the shuttle through the warp. result can be accomplished by a relatively quick motion of the harness frames while the lay is in forward position with the 20 shuttle boxed. It is found, however, that with the great variety of fabrics which are woven any fixed relation between fast and slow motions on the part of the dobby knives will impose objectionable limitations.

It is an important object of my present invention to provide a planetary gear drive for the knives, the solar gear being fixed around the axis of the driving shaft and meshing with a planet gear on an arm of the shaft and having a cross head on which is mounted a roll passing through the driven lever for the knives. The

picking and other motions of the loom will ordinarily be fixed in their time relation with respect to the bottom shaft, and by loosening the arm and holding the planet stationary, the shaft is turned until the desired angular relation be.- tween the picking and gearing is attained, after which the arm is tightened to the shaft to hold the new setting.

The bottom shaft ordinarily rotates once for every two complete beats of the loom and turns at a uniform rate. By reason of the structure to be set forth hereinafter the dobby knives are given a complete cycle of motions every other 45 beat of the loom but their rates of motion are irregular, being faster at times than the motion of the bottom shaft, and slower at other times, during each beat of the loom.

With these and other objects in View which 50 will appear as the description proceeds, my invention resides in the combination and arrangement of parts hereinafter described and set forth.

In the accompanying drawings, wherein a con- 55 venient embodiment of my invention is set forth,

l is a front elevation of one end of a loom having my invention applied thereto,

Fig. 2 is an end view looking in the direction of arrow 2, Fig. 1,

Fig. 3 is an enlarged detail looking in the direction of arrow 3, Fig. 1,

Fig. i is a vertical longitudinal section taken on line 43- 3 of Fig. 3,

Fig. 5 is a detail vertical section on line 55 of Fig. 4,

Fig. 6 is a horizontal section on line 6-43 of Fig. 5,

Fig. '7 is a vertical section on line 'l'l, Fig. 4,

Figs. 8 and 9 are diagrammatic views showing the relation of the different parts of the motion throughout one complete pick of the loom, and

Fig. 10 is a graph setting forth the character of motion of the knives when driven by my invention as compared with the usual crank motion drive.

Referring particularly to Figs. 1 and 2, I have shown a loom frame in on the upper end of which is. mounted the dobby H having a rocker arm 52 pivoted at it. The rocker arm carries upper and lower links M and 15, respectively,

' which are attached to the upper and lower knives it and il, respectively. A rear rocker arm :8 also connected to the knives and moving with rocker arm l2 has a driving arm E9 to be raised and lowered by an upright arm to reciprocate the knives. Other parts of the dobby are omitted for the sake of clearness, but it is to be understood that the knives cooperate with hooks, dobby back levers and harness jack levers not shown but all well understood and similar for instance to the structure shown in my prior Patent No. 1,674,010.

The loom has the customary top and bottom shafts '25 and 26, respectively, connected by gearing indicated at 27, Fig. 2, to turn the bottom shaft once for each two beats or picks of the loom.

The matter thus far described may be of common construction and relates to the usual type of loom employing a dobby, and of itself forms no part of my present invention.

In carrying my invention into effect I provide the loom with an end frame having a bearing 3! through which shaft 26 extends, as indicated in Fig. 4. The bearing is provided with a turned section 32 on which is mounted a solar gear 33 concentric with the shaft 26 and having a web 36 provided with a series of square openings 35, see Fig. 5. The bearing 3! is provided with arouate slots which are at the same radial distance from shaft as the square holes 35, and securing bolts 31 pass through the slots .and selected square holes to hold the solar gear 33 in fixed adjusted angular position with respect to the bearing 3|. The slots 35 may be of sufficient length to permit a continuous angular adjustment of the solar gear around the shaft 25.

Secured to shaft 26 is a driving arm the hub 4! of which may bev split as at 42 to receive a clamp bolt 43, and a key 44 in hub 4| is forced against the shaft 26 by screws 58 to act with clamp bolt 43 to hold the arm in adjusted angular position on the shaft.

As illustrated in Fig. 4 the upper part of arm 45 is provided with a roller bearing 45 through which extends a stub shaft 46. End plates 4'! confine the roller bearing to the upper part of arm 40, and an inner shell 48 fastened to shaft 46 is spaced from a second shell 49 secured to the arm 40 by rolls 55. I do not wish to be limited to the particular type of bearing for the stub shaft set forth herein. 7

A planet gear or pinion is keyed as at 56 to the stub shaft 46 and meshes at all times with the solar gear 33. The planet gear has half the number of teeth of those in the solar gear, so that as the bottom shaft makes a complete revolution carrying the arm 48 and pinion 55 through one complete circle the latter is caused to rotate twice on its axis.

The shaft 46 has secured thereto a cross head slotted as at 5| and having opposed ribs 52 to confine the head 53 of a bolt 64. The latter extends through a bushing 55 on which is mounted a. roll 66. A washer B7 and nut 68 hold the roll at a fixed distance from the axis of pinion 55, and the adjustable feature permits this distance to be varied.

A driving lever 15 for the lower end of rod 29 has a hub H fitting a bushing 12' fixed to the shaft 26 by a screw 13, as indicated in Fig. 4. Lever ill has a slotted driven arm 14 through which extends a bolt 15. The latter has a head 15 and a nut Tl by means of which a bushing i8 may be clamped to the arm 14 at selected distances from the axis of bottom shaft 25. A swivel head 19 on bushing 18 affords pivotal connection as at for the lower end of the rod 25. By reason of the connections just described rota- 7 tion of driven arm 14 about shaft 26 will raise and lower rod 25.

As shown in Fig. 4 there is formed on the lever '15 an upwardly extending arm which has a relatively long and large slot 85 in which closely fits the previously described roll 65. The slot 85 extends on each side of the axis of stub shaft 45 for a purpose to be described.

In normal loom operation shaft 26 will rotate at a uniform speed and complete half a revolution every beat of the loom. The arm 45 will therefore swing through 180 for each beat of the loom, and since the fixed solar gear 33 has twice the number of teeth of the planet gear or pinion 55, the latter will make one complete rotation on its axis as it makes a half revolution about shaft 26. cross head 68 will also rotate, causing the roll 55 to swing around said pinion axis and move along slot 86.

As arm 40 moves to the right from the position of Fig. 3, pinion 55 will be given a right hand rotation about its axis and roll 65 and arm 85 will move to the left relatively to arm 40 until arm 55 is at right angles to the line joining shafts 25 and 46. During this time arm 85 has been turn- As the planet gear rotates on its am's theing at a rate slower than the rate of arm 40, starting from the Fig. 3 position with the lowest rate and attaining the rate of arm 45 when the aforesaid right angle relation is reached.

Continued turning of arm it makes roll 55 approach a line passing through shafts 25 and 45, thereby causing arm 85 to travel angularly at a rate faster than that of arm 45, the rate becom-- ing a maximum when parts 25, 45 and 64 are aligned. Further rotation of arm 55 results in a slackening of the rate of arm 85 until arm 60 again reaches a position at right angles with the line joining shafts 25 and 45. The arm 85 at this time again moves temporarily at the same rate as arm 55.

Further rotation of arm 45 again causes bolt 64 to approach the line joining shafts 26 and 46, producing a shift of arm 85 to the left relatively to arm 45 until the parts again assume the relative position shown in Fig. 3, but with the pinion under the solar gear.

When bolt at is moving from a position at the left of shaft 46, Fig. 3 to a position at the right of said stud, arm 85 moves in the same direction as does arm ll) and the excess in the rate of arm 85 over that of arm .5 is added to the rate of the latter, therefore arm 85 and hence lever ll] moves fastest when roll 55 is beyond stub shaft 45 relatively to shaft 25. This is the condition of fastest motion of the knives when the harnesses are crossing and the shuttle is boxed.

When bolt 65 is between shafts 45 and 25, however, the difference in rate between arms 48 and 85 is subtracted from the rate of arm 45, hence at this time th arm 85 and lever it move slower than does arm 523. This is the condition of slowest motion of the knives, with the shuttle in flight.

The effect of these differential speeds is shown in Figs. 8 and 9. In Fig. 8 the rod 25 is substantially at the beginning of its up motion corresponding to the time that the lay L is moving forward and the harnesses begin their crossing. As shown in this figure an angular motion of on the part of shaft 25, indicated at the right of the figure, produces a relatively large angular motion of arm 714, this motion exceeding 90. The harnesses are therefore moved quickly when the shuttle is out of the shed and the lay is forward.

The succeeding 90 of motion of the bottom shaft is shown diagrammatically in Fig. 9, where it will be seen that during the next one-quarter revolution of shaft 25, indicated at the bottom of Fig. 9, there results an. angular motion on the part of arm 14 which is considerably less than 90. As arm 14 moves from the full to the dotted line position in Fig. 9 the knives are at or near their extreme position, and as is clearly apparent from this figure the motion of the harnesses is slow, the rate being considerably less than would be the case were this arm connected directly to the bottom shaft. The condition. of Fig. 9 exists when the lay is in its rear position and when it is desirable to maintain the shed open to permit flight of a shuttle.

In Fig. 10 the vertical lines 98 represent equal angular displacements of arm 40, light line 9| indicates a crank or simple harmonic motion such as that derivable directly from arm 40. The heavy solid line 92 represents the character of motion produced by my invention with the parts starting their motions. from the position of Fig. 3, that is, with axes '26, 64 and 46 vertically aligned when the rod 20 is in lowest position. The dotted line 93 indicates a phase displacement with the said axes as before but with the rod at a position other than lowest.

The start of the rising motion of rod 20, indicated by the heavy line 92 in Fig. 10, is slower than the crank motion shown by line SI, and reaches a given position near its upper limit of motion before it would if moved by a crank motion. The upper and lower ends of line 92 repre- 10 sent dwells of the knives to permit flight of the shuttles.

When assembling the parts the solar gear will he slipped on to the hub 32 and left free to rotate thereon, after which the arm 40 carrying 15 the pinion and cross head and also the key M will be slid along the bottom shaft 26 until the pinion 55 meshes with the solar gear, no particular attention at this time being paid to the angular relation of the parts. If the hub of 20 the lever 46 fits tightly it may be necessary to oscillate it angularly about the shaft to slide it to the position shown in Fig. 4, the looseness of the solar gear permitting this motion. When the arm is finally in the desired longitudinal po- 2 sition along the bottom shaft it may be that the solar gear will be in the angular position indicated by the dotted line position of the bolts 31 in Fig. 5 and the cross head may be in some such position as indicated in dotted lines in Fig. '7.

30 The solar gear is then turned to cause rotation of the pinion until the cross head assumes the position shown in Fig. 3, after which the set screws 38 are tightened to force the key 44 against the shaft 26 and the clamp bolt 43 is also 35 tightened. The bolts 31 are passed through the web 34 and secured in position as suggested in Fig. 6. The lever and its bushing 12 are then fitted with the roll 66 in the slot 85.

Several adjustments are possible with the 40 structure hereinbefore described. If it be desired to vary the length of the throw of the knives without altering the character of their motion or their phase relation with respect toother parts of the loom, the bolt will be 45 moved along the arm 14 to rock arm I!) of the dobby the desired amount. If, on the other hand, it is desired to change the character of the knife motion, that is alter the manner in which it deviates from a crank motion, the bolt 50 64 will be loosened with respect to the cross head and moved toward the axis of stub shaft 46 if it is desired to approach a crank motion, or moved away from that axis if a greater deviation from a crank motion is desired.

If the character of the knife motion is to remain the same but its phase relation with respect to other parts of the loom is to be altered, the set screws 38 and clamp bolt 43 will be loosened, thereby permitting the shaft 26 to be 60 turned with respect to the arm 10 to any desired adjusted position while maintaining the planet pinion 55 unchanged in the position for instance shown in Fig. 3. The set screws 38 and bolt 43 are then tightened to maintain the new 65 phase relation. This adjustment can be made .75 angular movement about shaft 26 to cause partial rotation of the planet pinion 55, after which the solar gear is again fastened in its newly adjusted position. The effect of this adjustment is to cause the roll 66 to be nearest the bottom shaft 26 when the longitudinal axis of lever I'll is at a slight angle with respect to a vertical line passing through the bottom shaft.

From the foregoing it will be seen that I have provided a simple planetary gear drive for the knives of a dobby operating in such a manner as to cause a rapid crossing of the harness frames when the lay is in the forward part of its stroke and the shuttle is boxed, and serving to maintain the sheds open a relatively long time when the lay is in the rear part of its stroke and the shuttle is in flight. Furthermore, the character of the knife motion, in the extent by which it deviates from a crank motion, can be changed by altering the position of the roll 66. Again, if a change in the fabric being woven in the loom demands an alteration of the phase relation between. the harness motion and some other part of the loom, such for instance as the picking, the arm 40 and bottom shaft 26 which drives the picking for instance, can have their relative angular positions altered. It will also be seen that an addition method of adjustment is provided by making the solar gear capable of assuming several adjusted positions angularly with respect to the shaft 26.

Having thus described my invention it will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the in vention and I do not Wish to be limited to the details herein disclosed, but what I claim is:

1. In driving mechanism for a loom dobby having a pair of. oppositelyreciprocating knives, a rotating shaft, a fixed solar gear concentric with the shaft, a pinion meshing with the solar gear and movable about the shaft and rotatable about an axis spaced from the shaft, a lever movable about the shaft, a driving connection between the pinion and the lever to exert a driving force on the lever and rotatable about the axis of the pinion and driving connections between the lever and knives.

2. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, an arm fixed to the shaft, a pinion supported by the arm and rotatable about an axis spaced from. the shaft, a fixed solar gear meshing with the pinion, a roll rotating with the pinion about an axis spaced from the axis of said pinion, a lever rotatable about said shaft and driven by the roll as said arm rotates with the shaft, and connections between the lever and knives.

3. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, an arm secured to and rotating with the shaft, a pinion supported by and rotatable with respect to the arm about an axis spaced from the shaft, 2. fixed solar gear concentric with the shaft and meshing with the pinion, a cross head rotatable with the pinion, a lever rotatable about the shaft, a driving connection between the cross head and the lever to apply driving force to the lever at points spaced from the axis of the pinion, and driving connections between the lever and knives.

4. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, an arm secured to the shaft, a

pinion rotatable on the arm about an axis spaced from the shaft, a'fi'xed solar gear meshing with the pinion, a lever movable about the shaft, an arm forming part of the lever and having a slot therein, means in the slot and rotating with and about the axis of the pinion to transmit a force from the pinion to said arm forming part of the lever, and driving connections. between the lever and knives.

5. In a driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, an arm fixed to the shaft, a pinion supported by the arm and rotatable about an axis spaced from the shaft, a fixed solar gear concentric with the shaft and meshing with the pinion, a cross head rigid with respect to the pinion and rotating therewith, a lever rotatable about the shaft, means to establish a driving connection between the cross head and the lever at any one of a plurality of points at different distances from the axis of the pinion, and driving connections between the lever and the knives.

' 6. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, a fixed solar gear concentric with the shaft, an arm secured to the shaft, a pinion meshing with the solar gear and supported rotatably with respect to the arm, a cross head having a slot formed therein and movable with the pinion, a lever rotating about the shaft, means including an element to be held at any one of a plurality of positions in the slot at different distances from the axis of the pinion to transmit force from said pinion to the lever, and driving connections between the lever and knives.

'7. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, an arm secured to the shaft, a solar gear concentric with the shaft, means to hold the solar gear stationary in any one of a plurality of. angular positions, a pinion meshing with the solar gear and supported by and rotatable with respect to the arm, a lever rotatable about the shaft, driving connections between the pinion and the lever to transmit a force from the pinion to the lever at points spaced from the axis of the pinion, and driving connections between the lever and knives.

8. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, a fixed solar gear concentric with the shaft, a pinion meshing with the solar gear and movable about the shaft, a lever movable about the shaft, a driving connection between the pinion and the lever to exert a driving force on the lever at points spaced from the axis of the pinion, driving connections between the lever and knives, and means to hold the solar gear stationary in any one of a plurality of different angular positions.

9. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, a solar gear concentric with the shaft, means. to hold the solar gear in any one of a plurality of fixed angular positions, a pinion meshing with the solar gear and rotating about the shaft and also about an axis spaced from the shaft, a cross head movable with the pinion, a lever rotatable about the shaft, means to establish driving connections between the cross head and the lever at any one of a plurality of points at different distances from the axis of the pinion, and driving connections between the lever and knives.

10. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives,

a rotating shaft, a driving'lever' for the knives concentric with and rotatable about the shaft, and driving connections between the shaft and the lever including a fixed gear meshing with a pinion rotatable bodily about the shaft and. ef-

fective during a one-quarter revolution of the shaft to give the lever an angular motion less than and effective during the next one-quarter revolution of the shaft to give said lever an angular motion greater than 90.

11. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, an actuating lever forthe knives rotatable about the shaft, and driving connections interposed betwen the shaft and the lever and including two constantly meshing gears one of which is fixed and the other of. which rotates about an axis which revolves about the axis of the shaft and is effective during a given one-quarter revolution of the shaft to move the lever through an angle less thanl90f, and effective during the next one-quarter revolution of the shaft to move said lever through an, angle greater than 90.

12. In driving mechanism for a loom dobby having a pair of oppositely reciprocating knives, a rotating shaft, a knife driving lever rotatable about the shaft, and driving means interposed'be tween the shaft and the lever including two meshing gears one of which is concentric with the shaft and the other of which rotates about an axis which revolves about the shaft, said driving means effective during a given one-quarter revolution of the shaft to move the lever by a force derived from the meshing gears'through" shaft, a planet pinion meshing with the solar gear, I

an arm moved by the shaft and supporting the planet gear, a lever concentric with the shaft, dobby knives having driven relation withrespect to the lever, connections between the planet gear and the lever to move the latter by force derived from the planet gear and exerted on said lever at points removed from the axis of theplanet gear, and means to vary the angular setting of the arm with respect to the shaft to the end that the phase relation between the movements of the knives can be loom part. 7

14. In a loom, dobby knives, a rotating shaft, a loom part driven by and having acycle of opaltered with respect to said erations thereof in fixed time relation with re spect to the rotating shaft, a fixed solar gear con centric with the shaft, a pinion meshing "with the solar gear and movable about the shaft, a lever movable about the shaft, a driving c'o'nnec tion between the pinion and the'lever to exert a driving force on the lever at points spaced from the axis of the pinion, driving connectionsbetween the lever and knives, and means'to vary the angular relation between the axis of the pinion and the rotating shaft to the end that the phase relation of movements of the knives can be altered with respect to the cycle of said loom part.

15. In a loom, a rotating shaft, a'loom part driven by the shaft and having a cycle of movements determined by said shaft and in fixed time relation with respect thereto, dobby knives, driving connections between the rotating shaft and the dobby knives including a fixed solar gear concentric with the shaft and a planet pinion meshing with the solar gear and supported by and rotating with a shaft, and. means to hold the planet pinion with the axis thereof in any one of a plurality of different positions around and with respect to rotating shaft to the end that the phase relation between the movement of the knives caused by said means can be altered with 5 respect to the cycle of said loom parts.

ELBRIDGE R. HOLMES. 

